Wysocki L J, Margolies M N, Huang B, Nemazee D A, Wechsler D S, Sato V L, Smith J A, Gefter M L
J Immunol. 1985 Apr;134(4):2740-7.
The humoral immune response in strain A mice to protein conjugates of p-azophenylarsonate (Ars) is characterized by the presence of a major cross-reactive idiotype denoted as IdCR. Previous molecular analyses of monoclonal IdCR+ Ars-binding antibodies isolated from multiply immunized animals have indicated that these antibody variable (V) regions may be the expressed product of a single combination of VH, D, JH, V kappa, and J kappa gene segments. The basis of this apparent domination of the Ars response by V regions encoded by this single combination of gene segments is unclear, but is discussed in this report. Our structural analyses on five monoclonal IdCR+ antibodies that are unable to bind Ars show that in contrast to those of Ars-binding IdCR+ antibodies, these (Ars-nonbinding) IdCR+ V regions are encoded by multiple combinations of VH, D, JH, V kappa, and J kappa gene segments, but with the commonality that they all utilize a single VH gene segment (VHIdCR). We provide examples in which the VHIdCR gene segment is expressed with three different V kappa gene segments and with each of the four JH gene segments to produce serologically detectable IdCR+ Ars-nonbinding antibodies. It would thus appear that the previous failure to detect alternative IdCR+ V segment combinations was due to a sampling procedure requiring that the IdCR+ antibody bind Ars, and not the result of restricted assembly or expression of the VHIdCR gene segment with a particular combination of D, JH, V kappa, and J kappa gene segments. This bias in protocol, however, cannot completely account for the homogeneity in previously studied IdCR+ Ars-binding antibodies, because we were able to isolate, from primary immune responses, IdCR+ antibodies that do bind Ars but that utilize alternative V segment combinations. This finding suggests that combinations of V gene segments encoding IdCR+ antibodies are more numerous in primary as opposed to secondary immune responses, and raises the question of why a single combination of VH, D, JH, V kappa, and J kappa gene segments dominates the secondary strain A immune response to Ars.
A品系小鼠对对氨基苯胂酸（Ars）蛋白偶联物的体液免疫反应的特征是存在一种主要的交叉反应独特型，称为IdCR。先前对从多次免疫动物中分离出的单克隆IdCR + Ars结合抗体的分子分析表明，这些抗体可变（V）区可能是VH、D、JH、Vκ和Jκ基因片段单一组合的表达产物。由该单一基因片段组合编码的V区在Ars反应中这种明显占主导地位的基础尚不清楚，但本报告对此进行了讨论。我们对五种无法结合Ars的单克隆IdCR +抗体进行的结构分析表明，与Ars结合的IdCR +抗体不同，这些（Ars不结合）IdCR + V区由VH、D、JH、Vκ和Jκ基因片段的多种组合编码，但它们的共同之处在于都使用单个VH基因片段（VHIdCR）。我们提供了一些例子，其中VHIdCR基因片段与三种不同的Vκ基因片段以及四个JH基因片段中的每一个一起表达，以产生血清学上可检测到的IdCR + Ars不结合抗体。因此，先前未能检测到替代的IdCR + V片段组合似乎是由于一种采样程序要求IdCR +抗体结合Ars，而不是VHIdCR基因片段与特定的D、JH、Vκ和Jκ基因片段组合进行受限组装或表达的结果。然而，该方案中的这种偏差并不能完全解释先前研究中IdCR + Ars结合抗体的同质性，因为我们能够从初次免疫反应中分离出确实结合Ars但使用替代V片段组合的IdCR +抗体。这一发现表明，与二次免疫反应相比，编码IdCR +抗体的V基因片段组合在初次免疫反应中更多，并提出了一个问题，即为什么VH、D、JH、Vκ和Jκ基因片段的单一组合在A品系小鼠对Ars的二次免疫反应中占主导地位。
